Tag: Anolis sagrei Page 2 of 5

JMIH 2017: Brown Anole Reproductive Output Varies Seasonally

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Tim Mitchell, Josh Hall, and Daniel Warner: Seasonal Shifts in Anolis sagrei Reproduction Invoke Challenges for Scientific Reproducibility

Sometimes a scientist just needs hundreds of hatchling anoles for an experiment. Tim Mitchell found himself in this position recently, and, like a good lizard ecologist, he started breeding colonies of anoles in the lab to produce eggs to incubate until hatching. As he created three different breeding colonies from brown anoles (Anolis sagrei) in central Florida, one each in February, June, and September, Tim found that he had also created an ideal situation in which to examine how the reproductive condition and output of brown anoles varies across the breeding season.

Tim, along with his coauthors Josh Hall and Dan Warner, found that females produced eggs with significantly greater mass later in the breeding season. These eggs took longer to produce than those earlier in the year (a greater interclutch interval), and the eggs resulted in hatchlings that had higher mass in relation to the weight of their eggs. These reproductive differences remained even after accounting for the fact that female anoles were also larger and heavier later in the year.

These findings suggest that female A. sagrei may shift their reproductive effort from producing a higher quantity of eggs (i.e., more, smaller eggs resulting in smaller hatchlings) in the beginning of the breeding season, to producing higher quality eggs (i.e., fewer, larger eggs resulting in larger offspring) later in the breeding season. Tim’s findings also stress the importance of investigating and accounting for seasonal differences when examining reproductive output in lizards.

 

Female Brown Anole Inspecting Nest Pot

It is not new to most of us that female lizards choose between different nest sites (e.g. Shine & Harlow, 1996; Warner & Andrews, 2002), anoles included (Socci et al., 2005; Reedy et al., 2012 – covered on Anole Annals). But what is new to me is how females assess soil characteristics to decide where to lay their eggs.

Brown anoles in an intimate moment.

Brown anoles in an intimate moment.

For context, I recently started to breed brown anoles in the lab for the first time. I’m using large vertical screen cages in an outdoor set up, which I believe makes them pretty comfortable to keep their daily anole life. There have been lots of  male-male interactions (displaying and serious fights), mating and nesting.

A few days ago I started to notice females head down in the nests pots, breathing heavily from time to time. I wondered if they were inspecting the nest pots before laying and shared a video on Twitter. They take a long time in that position, which made me really curious to know how they assess their chosen nest-site characteristics. Let me know if you know more about it. Posted above is the video I uploaded to youtube.

I feel so lucky to be able to observe all these cool behaviors and I hope to share some more soon!

JMIH 2016: Rock ‘n’ Bowl Anole

At the JMIH in New Orleans this past July, the 100th anniversary celebration of the ASIH was held at the Rock ‘n’ Bowl, where music, food, drink, dancing, and bowling were enjoyed by all. But for those who were alert on their way in, there was an added bonus: anoles! Or, at least, one anole, spotted by Quynh Quach and corralled by Kristin Winchell.

Quynh and Kristin spot their quarry.

As other attendees file in, Quynh and Kristin spot their quarry in the bushes.

Taking a picture of the crowd filing in, I serendipitously caught our two intrepid anoleers  about to make the catch in the bushes to the right of the entrance. Kristin made the grab, and displayed her catch.

Kristin displays the catch.

Kristin displays the catch.

It was, of course, Anolis sagrei, the invasive Cuban species which has been spreading through the southeastern US for more than 80 years now. He was a nice-sized adult male, typical of the nominate form that occurs through most of the species’ US range.  The edificarian habitat– in bushes at the edge of a parking lot next to a building– is also typical of where invasive sagrei can be found.

Adult male Anolis sagrei, New Orleans, Louisiana, 10 July 2016.

An appreciative crowd gathered.

Eager anolologists immortalize the NOLA anole in pixels.

Eager anolologists immortalize the NOLA anole in pixels.

I was glad to see it, because prior to this I had only seen Anolis carolinensis in New Orleans (more on this in a later post).

Quyhn and Kristin show off their catch.

Quynh and Kristin show off their catch.

 

Notes from the Field: Predation on Anolis sagrei on Isolated Cays in Abaco, Bahamas

Curly tail with brown anole tail visible from its mouth

Curly tail with brown anole tail visible from its mouth

Kayaking to the cays

Kayaking to cays

I was recently in Abaco, Bahamas with Losos lab post-doc Oriol LaPiedra and Ph.D. candidate Darío Fernández-Bellon from University College Cork, Ireland, to carry out some behavioral studies of Anolis sagrei on the island and its surrounding small cays. We kayaked (a highly recommended transportation mean for its lesser-impact on the marine ecosystem, not having to rely on the tide schedule, while allowing you to see rays and sharks and sea turtles!) our way out to islands that are known to have A. sagrei naturally existing alone, or with one of their natural predators, Leiocephalus carinatus.

Curly-tailed lizards are known to prey on A. sagrei and can have significant impact on anole behavior and adaptation. Twice I observed Leiocephalus capturing and consuming A. sagrei, one of which was an adult male and the other an adult female. We have also noticed that the A. sagrei on these island tend to perch higher and are seldomly seen on rocks or leveled ground compared to those on islands without curly tails, so this behavior could be an effect of Leiocephalus being present.

A female red-winged blackbird with a brown anole in its beak

A female red-winged blackbird with a A. sagrei in its beak

On a different island where Leiocephalus were absent, A. sagrei are still under predation pressure, this time by red-winged blackbirds nesting on the island. We observed a female blackbird with an A. sagrei in its beak waiting for us to leave the island so that it can feed its chicks. This observation suggests that A. sagrei on islands without Leiocephalus might still be under predation pressure by other species that might not be present on the island at all times. Also, predation pressure exerted by an aerial predator differs from that by a terrestrial predator or if both predators are present, so this might be a factor in morphological or behavioral changes in these lizards on these islands.

Anolis sagrei on one of the small cays

Other interesting observations include A. sagrei density on islands seems to be unintuitive. Some small islands with fewer perches hosted many more adult males and females than large islands did. Sizes of individuals also seem to vary greatly between different islands: small cay A. sagrei seem to be, on average, larger than those on mainland Abaco. Personally, I am unable to note major differences between islands which might have resulted in these observations. I’m excited to see if the data we’ve collected will give more insight into these observations as well as other behavioral results that will come from this study!

Evolution 2016: It’s Getting Cold in Here!

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Tamara Fetters with her poster at Evolution 2016

Tamara Fetters, from the McGlothlin lab at Virginia Tech, reported on her ongoing work on thermal physiology in Anolis sagrei during the first poster session here at Evolution 2016 in Austin, Texas. Tamara looked at thermal tolerance and sprinting abilities at different temperatures and how that related to the latitude of the population. Specifically, she asked if lower temperatures regularly experienced by the Northern populations influence cold tolerance and performance at those temperatures. She expected that Anolis sagrei, native to Cuba and the Bahamas and introduced into the Southern U.S., would show signs of adaptation to its new, colder home in the more Northern mainland populations compared to the native range island populations in the South.

Tamara’s poster focused on two main experiments. In the first she calculated thermal tolerance to cold temperatures using a classic critical thermal minimum (CTmin) setup: with an ice bath she slowly lowered the body temperature of each animal until it was unable to right itself. This method approximates the minimum temperatures that the animals can handle in the wild. She found a clear trend showing a decrease in the minimum temperature tolerated as latitude increased. In short, Northern populations could handle the cold and Southern populations could not.

In the second experiment, Tamara acclimated the lizards to 6 temperatures ranging from 12-41 °C before running them up a track to calculate sprint speed. Tamara used an impressive 25-50 animals from each of 5 populations! She calculated sprint speed from the high-speed video she took using the program Kinovea. Tamara found that across all temperatures the most Southern population ran the slowest while the most Northern population ran the fastest, with the differences remaining fairly constant.

So what’s next for Tamara? She is planning on rearing animals in a common garden setup with some animals in hot temperatures with low variability between day and night (mimicking the native range, Southern habitats) and some animals in cool temperatures with high variability between day and night (as is experienced in the Northern habitats). She hopes that these studies will help her understand the genetic basis of this thermal tolerance and the extent of plasticity in thermal adaptation.

One last note – Tamara wanted to thank Anole Annals for helping her determine her study locations. She was able to determine which areas were likely to have Anolis sagrei and how far North they have spread because of Anole Annals posts (like this one) and comments.

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Click to view a bigger version of Tamara’s poster

Age- and Sex-Specific Variation in Habitat Use by Brown Anoles

Little guys like it narrow. Photo from Daffodil’s Photo Blog.

The influence of habitat use on ecological and evolutionary patterns in Anolis lizards is well documented. Despite extensive work on interspecific variation, how habitat use varies within a species is relatively understudied.

As part of my master’s work in Dan Warner’s lab, we caught and recorded the perch height, width, and substrate (i.e., ground vs. vegetation) of 717 brown anoles (A. sagrei) on a small island in the Halifax River, near Ormond Beach, Florida. The island consisted of two main habitat types (open-canopy and forest) with an intermediate between the two.

Notes from the Field: Another Successful Bahamian Adventure

AbacoI just got back from a trip to the Bahamas with Losos lab post-docs Anthony Geneva and Alexis Harrison, accompanied by expert lizard catchers Inbar Maayan and Sofia Prado-Irwin (Harvard graduate student). We parted ways for the first few days of the quick trip, with Anthony and Sofia headed to Bimini and Alexis, Inbar, and myself on Abaco. Read more about the Bimini trip in Sofia’s recent post.

Deck at the Friends for the Environment Kenyon Center field station

Friends for the Environment Kenyon Center field station

On Abaco, we stayed at the brand new Friends of the Environment Kenyon Center. We were really impressed by the great accommodations of this field station. The station was sustainably built and had all the modern amenities we could wish for. The field lab was large and equipped with microscopes and plenty of counter space. We were equally impressed by the staff and their outreach efforts. The Friends for the Environment does a fantastic job providing nature education to local kids from age 3 through college! Their ambitious organization seeks to provide high-quality and low-cost facilities for visiting scientists and to provide outreach and education to the local community. We spoke with the coordinators of the organization who told us that any time researchers are looking for extra hands in the field they are happy to arrange local students to assist. We strongly encourage others traveling to Abaco to stay here!

In the end we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught.” – Baba Dioum (posted at the Friends for the Environment)

Our main goal on this trip was to capture Anolis sagrei to continue ongoing research into the amazing diversity among islands in this species. We were immediately struck by how much smaller the Anolis sagrei on Abaco were compared to those on the other islands we have been to. I was also struck by how many A. sagrei used the ground. I normally study Anolis cristatellus, and although they are the same ecomorph, I rarely see A. cristatellus on the ground. I also don’t recall seeing A. sagrei frequently on the ground on Bimini or Eleuthera. So observing these lizards, particularly the females, on the ground at such a high frequency (they literally scattered as I walked!) was very surprising. Is this common on other islands with A. sagrei and I just haven’t noticed before?

As with any good field trip, we also encountered a great diversity of herps. Although the only native anole to Abaco is  A. sagrei (according to Powell and Henderson 2012), we also saw plenty of Anolis distichus and a few Anolis smaragdinus. We also saw the invasive Cuban tree frog (Osteopilus septentrionalis), the native Eleutherodactylus planirostris, and plenty of curly-tails (Leiocephalus carinatus). No live snakes to report, although we did come across a couple of roadkill Cubophis.

Although we found no Sphaerodactylus, we did find plenty of non-native Hemidactylus. Interestingly, Hemidactylus is not listed in Powell and Henderson’s (2012) list of West Indian amphibians and reptiles for Abaco. Can anyone ID this species (the photos are of two individuals) and tell me if this has been reported before for Abaco? Obviously Hemidactylus are widespread in the Caribbean, but I was surprised to see it absent from the species list for many of the Bahamas islands.

Brown Anole Predation by Red-bellied Woodpeckers in Florida

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While visiting relatives last week in Fort Myers (FL), anole enthusiast and avid wildlife photographer Kyle Wullschleger noticed a commotion among the trees while on an afternoon hike in a small neighbourhood nature preserve. On closer inspection he witnessed a group of red-bellied woodpeckers (Melanerpes carolinus) foraging on surrounding cypress trees, with a couple eventually appearing with their apparent target–non-native Cuban brown anoles (A. sagrei). He recalls some of the details:

“The photos from the sequence aren’t all that fantastic because I cropped in so it really just shows the behavior. The whole sequence the woodpecker was basically just slamming the anole against the tree and then trying to pick it apart – it was hard to tell what exactly it was doing, but I believe it eventually swallowed it whole before flying away–it hopped behind the tree so I couldn’t see it anymore.”

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“There were at least five birds all moving up and down the lower third of the cypress trees just around the boardwalk I was on. They were moving around the trees without really knocking the wood, so maybe they were purposefully targeting anoles? I only saw successful predation twice, but the brush is so thick–it’s obviously happening quite a bit.”

Sean Giery had previously discussed the main avian predators of anoles in urban South Florida, but woodpeckers didn’t make the list. Woodpeckers do occur in urban areas of South Florida; a new one to add to the list?

Field Trip Recap: Herps of Bimini, The Bahamas

 

Searching for Anolis sagrei on the beautiful island of Bimini

Anolis sagrei on the beautiful island of Bimini

I just got back from a 10 day research trip to Bimini in the western Bahamas along with Harvard post-doc, Graham Reynolds, Harvard graduate student, Pavitra Muralidhar, and UMass Boston undergraduate, Jason Fredette. We went with the simple goals of kicking off a research project in the Losos lab on Anolis sagrei  and to observe as many other herps as we could.

We spent the majority of our time on South Bimini. We sampled from the well-maintained Nature Trail, where we found all four anole species (Anolis sagreiAnolis smaragdinusAnolis angusticeps, and Anolis distichus) and a Bimini boa among diverse habitat types, including blackland coppice and open Coccothrinax shrub. We also spent a couple of nights searching in some mangrove forest near the airport, which yielded only A. sagrei and A. angusticeps and in low abundance at that. The “Fountain of Youth” ended up being a gold mine for Sphaerodactylus nigropunctatus as well as boas — we caught 3 here.

We also did a fair amount of exploring. Our hosts for our house rental wanted to make sure we had a great time in Bimini and so they insisted on boating us out to a couple of the nearby islands for some snorkeling. They even provided us with the best full face snorkel mask I’ve ever laid my eyes on. We picked up a boat for the ride at the Intrepid Powerboats website. Of course, we saw this as the perfect opportunity to catch a few lizards. Our first destination was Gun Cay, a small island a few miles to the south of Bimini. Pavitra and Jason entertained our hosts by collecting shells and feeding stingrays. Meanwhile, despite our hosts’ curiosity that we wanted to go wander in the brush, Graham and I nabbed 10 adult male A. sagrei in less than an hour. We also saw several Ameiva auberiAnolis smaragdinus, and some sort of very large rodent (does anyone know about Hutia reintroductions in the Bahamas?).

The following day, our hosts insisted we come with them to a small island 20+ miles to the north of Bimini (Great Isaac Cay) where they promised us dolphins and hammerhead sharks. On the way to the island we saw several dolphins, tons of flying fish, sea turtles, and several large nurse sharks. As we approached the island, I saw the mature Casuarina forest and yelled down to Graham from the crow’s nest tower, “I want to go explore there!”  Our hosts got us as close as they could to the rocky shore (dangerously close it seemed, the hull almost hit the rocky karst island) and all four of us hopped onto the island. The island had an abandoned lighthouse and buildings from the 1800’s that we explored. We were shocked to not find a single anole on Isaac Island, although we did find Sphaerodactylus nigropunctatus and Ameiva auberi.

The isolated Great Isaac Cay with ruins from the late 1800's.

The isolated Great Isaac Cay with ruins from the late 1800’s.

The trip was a huge success. In total, we came across all but five of the reptiles of Bimini. Surprisingly, we were unable to find any Bahamian racers (Alsophis vudii) other than roadkills, though most of our field time was at night. Unsurprisingly, we did not find either of the blind snakes or the dwarf boa, the latter of which tends to be more common in the rainy season. As expected, A. sagrei was the most abundant anole on Bimini. We came across A. angusticeps and A. smaragdinus with equal frequency and actually encountered only a few A. distichus. We did most of our searching at night, so this may be a reflection on different sleeping behaviors rather than abundance.

In summary, we were able to observe:

  • 140+ Anolis sagrei males and females
  • Sphaerodactylus nigropunctatus (black-dotted dwarf gecko)
  • Sphaerodactylus argus (ocellated dwarf gecko)
  • Dozens of Leiocephalus carinatus (curly-tail lizard)
  • Chilabothrus strigilatus fosteri (Bimini boa)
  • a handful of Anolis distichusAnolis smaragdinusAnolis angusticeps

We also saw a number of other herps that we were not able to catch or didn’t need data from:

  • Ameiva auberi (Bimini ameiva)
  • Eleutherodactylus planirostris (greenhouse frog)
  • Osteopilus septentrionalis (Cuban tree frog)
  • Hemidactylus mabouia (invasive house gecko)

 

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Bolder Lizards Drop Their Tails More Readily to Compensate for Risky Behavior

(editor’s note: this video was added by the editor. Decide for yourself whether it illustrates the experimental approach described below)

It’s no secret that grabbing a lizard by its tail will often times leave you with the tail rather than the lizard. Why? Because the tail would simply break off. The voluntarily shedding of the tail in lizards (tail autotomy) has fascinated herpetologists ever since the 70s, and it didn’t take long for those people to notice that the propensity for tail autotomy varies extensively among species, conspecific individuals, or even within the same individual at different developmental stages. Four decades have passed, what might be responsible for the variation in tail autotomy is still not entirely clear. In a recent paper, we tried to solve a piece of the puzzle by testing the hypothesis that lizards might autotomize the tail with different propensities to compensate for their intrinsic risk-taking tendency.

Our idea was simple: bolder lizards, due to their behavioral tendency, tend to expose themselves more to higher predation risk. Therefore, selection might favor higher propensities for tail autotomy in bolder lizards as a compensation mechanism. We were also interested in knowing how food availability in the environment might affect tail autotomy. So, we caught a bunch of juvenile brown anoles from the same population in New Orleans and assigned them into two dietary groups: low versus high food availability. After the lizards reached adulthood, we picked out the males and examined the relationship between boldness and the propensity for tail autotomy. (In case you wonder how we measured the propensity for tail autotomy, we refer you to a paper by Stanley Fox, who contributed greatly to our knowledge of tail autotomy.)

And here’s what we found:

The relationship between boldness and the propensity for tail autotomy in the brown anole lizards

Bolder lizards did autotomize their tails more readily as a means to compensate for their risk-prone personality, but only in the group raised with abundant food. Our results helped explain why lizards from the same population autotomized the tail with different propensity. Moreover, our study highlighted the role of food availability in the cost-benefit dynamics of tail autotomy, which has never been explicitly discussed or tested before. Aside from those exciting implications for the study of tail autotomy, our results also have important bearings on broader topics such as the evolution of trait compensation and animal personality. If you are interested in knowing more about this project, check out our recent paper:

CHI-YUN KUO, DUNCAN J. IRSCHICK and SIMON P. LAILVAUX. (2014). Trait compensation between boldness and the propensity for tail autotomy under different food availabilities in similarly aged brown anole lizards. Functional Ecology DOI: 10.1111/1365-2435.12324

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